Gallium Nitride (GaN) has electrical and physical properties that make it highly suitable for high frequency (HF) and/or high power microwave devices. These devices produce a high amount of heat requiring a heat spreader to be attached to the devices to avoid device failure. One such heat spreader is diamond. A number of processes include forming diamond on a bottom surface of an HF and/or high power device opposite a top surface. The top surface of the HF device includes, for example, a source, a drain and a gate. In one example, a hot filament chemical vapor deposition (CVD) process has been used to form diamond that is used with GaN layers. Generally, these diamond layers are not deposited directly onto the GaN layers but onto some other material (e.g., silicon, silicon carbide, and so forth) that is eventually disposed with the GaN layer.